One of the best kept secrets in .Net development is the Microsoft Patterns and Practices group.  I think when Visual Studio .Net Team System comes out more people will realize what great input this group has had at Microsoft.  I have already talked about their Application Blocks and how I like them (although there are good Open Source alternatives as well like Log4Net and Nini).  But I have found that most of my Consulting Clients prefer and are more comfortable with Microsoft stuff.  Fine with me!  Well they just released 2 great new products first the Enterprise Library (which is the combination of the most commonly used application bocks as well as many needed updates to the app blocks) here (http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnpag2/html/entlib.asp).  They also have a new web site (http://patternshare.org/).  To get some of the vision of the group check out the two interviews (Ron Jacobs and Ward Cunningham) on one of my favorite websites http://www.theserverside.net/talks/index.tss.